Yang, On Tue, 12 Jun 2018, Yang Li wrote: > On Thu, Dec 28, 2017 at 4:17 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > > On Thu, 28 Dec 2017, Thomas Gleixner wrote: > > > > Sorry for the spam. I somehow missed to refresh the patch before generating > > the mbox. Find below the correct version of that one which has ALL braces > > removed which we don't need. > I'm not sure how we reached the conclusion that we should remove ALL > braces? I cannot find related discussion in the archive except for > the "WITH" case. https://lkml.kernel.org/r/CAOFm3uEpM_tBErkOvqghcy+wbw0i4mSnafPBRC3HYZVQjsSyMw@xxxxxxxxxxxxxx > This is conflicting with the current SPDX spec at > https://spdx.org/spdx-specification-21-web-version quoted below and > also the explenation in your own file. > > Quote from SPDX spec 2.1: More expressive composite license > expressions can be constructed using "OR", "AND", and "WITH" operators > similar to constructing mathematical expressions using arithmetic > operators. For the Tag:value format, any license expression that > consists of more than one license identifier and/or LicenseRef, should > be encapsulated by parentheses: "( )". This is not relevant here: For the Tag:value format, ..... The kernel does not generate SPDX files in Tag:value format. The kernel uses SPDX license identifiers to reflect the actual license of a file. > > + A <SPDX License Expression> is either an SPDX short form license > > + identifier found on the SPDX License List, or the combination of two > > + SPDX short form license identifiers separated by "WITH" when a license > > + exception applies. When multiple licenses apply, an expression consists > > + of keywords "AND", "OR" separating sub-expressions and surrounded by > > + "(", ")" . > > Conflicting with the example No, The keyword is 'separating sub-expressions'. It does not say license identifiers. So these examples are completely compliant with the documentation: > > + // SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note > > + // SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note > > + // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause Two license (exception) identifiers plus a operator. That's perfectly well defined. > > + // SPDX-License-Identifier: (GPL-2.0 WITH Linux-syscall-note) OR MIT This is actually a case where you need parentheses and they separate the sub-expression 'ID with EXC'. Adding extra parentheses around any simple 'ID operator [ID|EXC]' expression is really overkill and does not make stuff more readable. Likewise in programming languages. Why would anyone write: C et al.: a = (b || c); Pyhton: a = (b and c) Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
